Fire resistant mine door sealing system

ABSTRACT

A fire resistant mine door sealing system is disclosed for use in an underground mine passage, and includes a door panel pivotably mounted to a stoppage. A fire resistant seal member is positioned between the door panel and the stoppage to form an airtight seal therebetween, even when the door, stoppage and seal are subjected to high temperatures associated with a mine fire. The seal member comprises a high strength reinforced elastomeric seal having a plurality of elastomer layers and a plurality of reinforcing layers. At least one of the plurality of elastomer layers may have a flame retardant. The reinforcing layers are sandwiched between the elastomer layers to provide high strength and toughness. A method of manufacturing a fire resistant seal member is also disclosed.

FIELD OF THE INVENTION

The invention generally relates to an improved sealing system for a mine door, and more particularly to a reinforced mine door sealing system having enhanced fire resistance.

BACKGROUND

In underground mining, ventilation is a primary concern to ensure proper air quality for those personnel working underground. Accordingly, walls (commonly referred to as “stoppings”), often constructed of masonry materials, are erected to control ventilation within the mine, so as to block air flow through certain passages and to direct the flow of fresh air to other passages where miners are actively working. The stoppings also act as fire barriers in case of an underground mine fire to contain the fire and smoke between stoppings. Doors are built into the stoppings to allow movement of personnel and equipment therethrough. The door may be mounted on a structural frame that is fixed to the stopping.

To ensure that fire and smoke are adequately contained during a fire, a rubber seal may be installed between the door and the stopping frame. During a fire, however, such seals can burn, which can severely diminish the integrity of the seal. In addition, high temperatures associated with a fire can cause doors and frames to warp. If the seal remains intact, it may accommodate a moderate degree of door/frame warpage. However, if the seal burns or is otherwise substantially degraded, the airtight seal between the door and frame can be lost and the fire may be allowed to spread past the stopping, or, at the least, to allow smoke to flow between the door and the frame.

Prior systems have attempted to solve the seal degradation problem by eliminating the elastomeric material from the seal and replacing it with high temperature materials. In U.S. Pat. No. 5,956,902 to Cosby, a seal is disclosed as a specialized design formed by a woven fiberglass material surrounding a core of stainless steel inconel mesh in cable form. The Cosby design is resistant to heat-degradation because it is devoid of rubber material. The problem with such a design, however, is that the metal core material may not maintain its desired resiliency over long term use. Thus, it may be possible for gaps to form between the seal and the door and/or frame, which can allow smoke or fumes to pass in the event of a fire. Additionally, such a metal design may be relatively expensive to manufacture and replace compared to seals made from elastomeric materials.

Thus, it would be advantageous to provide a mine door sealing system that employs elastomeric compounds that will withstand the elevated temperatures associated with mine fires. It would be also desirable to provide a mine door seal that maintains a desired passageway seal even if the elastomeric compound suffers some degradation due to high temperatures. The desired sealing system will also be inexpensive to manufacture, install and replace.

SUMMARY OF THE INVENTION

The disadvantages heretofore associated with the prior art are overcome by the inventive design for a conveyor belt having a multiply needled felt design. The inventive design provides advantages including cost-effectiveness, efficiency and the desired strength as compared to previous designs.

A fire resistant mine door system is disclosed, comprising a mine door member, a mine stoppage member, and a resilient seal member. The resilient seal member may be disposed between the door member and the stoppage member to form an airtight seal between the door member and the stoppage member. The resilient seal member may comprise a plurality of elastomer layers and a reinforcing layer disposed between an adjacent pair of said plurality of elastomer layers. At least one of the elastomer layers may comprise an additive for enhancing the flame retardance of the seal member such that the seal member is capable of maintaining an airtight seal at temperatures up to about 500 degrees Fahrenheit.

A fire resistant mine closure is disclosed, comprising a mine door, a mine stoppage having an opening, and a seal member positioned between the mine door and a perimeter surface of the mine stoppage surrounding said opening. The seal member may form an airtight seal between the door and perimeter surface of the mine stoppage when the door is in a closed position with respect to the stoppage. The seal member may comprise first and second elastomer layers and a reinforcing layer. The reinforcing layer may be disposed between the first and second elastomer layers. The first and second elastomer layers may further comprise a flame retardant compound such that the seal is capable of maintaining said airtight seal at temperatures up to about 500 degrees Fahrenheit.

A fire resistant mine sealing system is disclosed, comprising a stoppage positionable within an underground passageway, a door panel pivotably connected to said stoppage, and a fire resistant seal member disposed between said stoppage and said door panel. The seal member may comprise a multilayered structure, the multilayer structure comprising a plurality of alternating elastomer and reinforcing layers. The fire resistant seal member may form an airtight seal between the door panel and the stoppage when compressed therebetween. The fire resistant seal member may further be capable of maintaining the airtight seal when the door and said stoppage are subjected to temperatures up to about 500 degrees Fahrenheit.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of the invention, both as to its structure and operation, may be obtained by a review of the accompanying drawings, in which like reference numerals refer to like parts, and in which:

FIG. 1. is an isometric view of an exemplary mine door system installed in a stoppage of a mine passageway;

FIG. 2A is an elevation view of a door frame element of the mine door system of FIG. 1;

FIG. 2B is an elevation view of an exemplary mine door of the mine door system of FIG. 1;

FIG. 3 is a cross section view, taken along line 3-3 of FIG. 1;

FIG. 4 is a detail view of a portion of FIG. 3;

FIG. 5 is a cross section view of an exemplary seal of the mine door system of FIG. 1;

FIG. 6 is a schematic illustration of a method of making a seal member for use with the door system of FIG. 1.

DETAILED DESCRIPTION

Referring to FIG. 1, an exemplary mine door system 1 is shown comprising a door 2, a frame 4 and a seal member 6. When the system 1 is used as a barrier in a mine application, the frame 2 may be mounted to a stopping 8 that has been erected in a mine passageway 10A, B. The stopping 8 may have an opening around which the frame 2 is fit, thus providing an opening for the passage of people and/or materials from one side of the stopping to the other.

In the illustrated embodiment, the door 2 is mounted to a rectilinear frame 4 that is mounted to the stopping 8. The door 2 may be pivotably mounted to the frame 4 by one or more hinges so the door 4 can be swung open and closed in a conventional manner to either enable or block passage through the opening in the stopping. The seal member 6 may be positioned between opposing sealing surfaces 12, 14 (see FIG. 3) of the door 2 and the frame 4 so that when the door is moved to a closed position with respect to the frame, the seal member 6 is compressed between the door 2 and frame 4, thus providing an airtight seal therebetween. The seal member 6 may be carried either by the door 2 or the frame 4.

It is noted that although the frame 4 is illustrated as being mounted to the stoppage 8, it could also be free standing or engaged with the roof and/or floor of the passageway 10. The frame may be mounted to the stopping 8 by bolting, welding, or other appropriate fastening arrangement. Additionally, in some embodiments, the frame 4 could be eliminated and the seal member 6 could seal directly against the stopping 8. The stopping 8 may be made from masonry materials, or it may be of metal construction.

Referring to FIG. 2A, the frame 4 may comprise a plurality of structural members 4A-4D, each of which may be secured to the stopping 8. In one embodiment, the structural members 4A-D comprise steel box beams welded together to form a rectilinear frame 4 having substantially the same dimensions as the door 2 to which it will attach. It will be appreciated that other shapes may be acceptable. The structural members 4A-D may have a sealing surface 14 suitable for engaging at least a portion of the seal member 6. In one embodiment, the sealing surface will be a substantially flat surface associated with one side of the box beams used to construct the frame 4. It will be appreciated, however, that other surface geometries may be used to advantageous effect. For example, a rounded or “V-shaped” sealing surface may be used to provide enhanced line contact between the frame 4 and the seal member 6 to ensure a desired contact between the two is achieved.

As previously noted, the door 2 may be pivotably mounted to the frame 4 so that the door can be swung open or closed in a conventional manner. Thus, one or more hinges 16 may be attached to one of the structural members 4A-D. The hinges 16 may be provided with springs (not shown) to bias the door 2 in the closed position against the frame 4. On a side of the frame 4 opposite to the hinge(s), a latch recess 18 may be provided to engage a latch 20 (FIG. 2B) of the door 2 to lock the door 2 to the frame 4 in the closed position. The design of the hinge, latch and latch recess 18 are conventional and will not be discussed in detail. An exemplary hinge and latch assembly is disclosed in U.S. Pat. No. 5,956,902 to Cosby, the entirety of which is incorporated by reference herein.

Referring to FIG. 2B, the door 2 may have a plurality of lateral or diagonal stiffening members 20A, B to provide strength and stability to the door 2 so that it may substantially maintain its shape when subjected to the high temperatures and pressures associated with a mine fire. Peripheral structural supports 22A-D may also be provided to ensure that the periphery of the door 4 (i.e., the portion that engages the sealing member 6) stays substantially flat during operation at high temperatures. This may be important to ensure that sufficient contact/compression exists between the door 2 and the seal member 6 to prevent smoke and fumes from passing therebetween. As previously noted, the elastic nature of the seal member 6 will accommodate minor distortions in the door 2.

The door 2 may have one or more latches 20 to engage the latch recess 18 of the frame 4 to lock the door 2 in the closed position. In one embodiment, the latch and latch recess are configured to lock together after a predetermined compressive force has been applied to the seal member 6, thus ensuring that an airtight seal is formed between the seal member 6 and the opposing sealing surfaces 12, 14 of the door 2 and frame 4.

FIG. 3 shows the position of sealing member 6 between the opposing sealing surfaces 12, 14 of the door 2 and the frame 4. Thus, the sealing member 6 is sandwiched between the door and frame to seal off passage portion 10A from passage portion 10B. FIG. 4 is a detail view of the engagement between the seal member 6 and the sealing surfaces 12, 14 of the door and frame. In the illustrated embodiment, the seal member 6 comprises a multi-ply reinforced seal having four individual elastomer layers 24A-D and three individual reinforcing layers 26A-C. It will be appreciated that other combinations of elastomer and reinforcing layers are contemplated.

Referring to FIG. 5, the seal member 6 may comprise a plurality of elastomeric layers 24 and a plurality of interspersed reinforcing layers 26. The outer elastomer layers 24A, D may form the sealing function against the door 2 and frame 4 as previously described. Thus, these layers 24A, D may have a composition and hardness (durometer) suitable for forming an appropriate airtight seal with the structural members when subjected to the compressive forces applied when the door 2 is latched to the frame 4. A relatively soft elastomer may enhance sealing where the structural members have surface imperfections or discontinuities (e.g., weld beads between members). In one embodiment, the elastomer may have a hardness of about 64 durometer Shore “A.” In addition, the outer elastomer layers 24A, D may be provided with a slightly roughened surface finish (i.e., sufficient to provide a “flat” or matte surface finish) to generally enhance engagement with the sealing surfaces 12, 14 of the door and frame.

The inner elastomer layers 24B, 24C may be made from the same material used to form the outer elastomer layers 24A, B, or they may be made from a different material. The inner layers also may have a different hardness than the outer layers. Since the inner layers serve to hold the reinforcing layers 26A-C together, they may be made from an elastomer composition that is well suited for forming a high integrity bond with the material used to form the reinforcing layers.

In one embodiment, the first elastomer layer 24A may have a thickness of about 0.188-inches, the fourth elastomer layer 24D may have a thickness of about 0.063-inches, and the second and third elastomer layers 24B, C may each have a thickness of about 0.024-inches.

Any of a variety of natural or synthetic elastomeric materials may be used to form the inner and outer elastomer layers 24A-D. A non-limiting list of exemplary materials includes polychloroprene (e.g., compound sold under the trade name Neoprene), chlorosulfonyl-polyetheylene, natural rubber, nitrile-butadiene rubber, butadiene rubber, isoprene, styrene-butadiene, modified polysiloxanes, polyester urethane, polyether urethane, polyvinyl chloride, fluorocarbon polymers, and the like. In a preferred embodiment, the elastomeric material comprises polychloroprene.

The elastomeric material may also comprise additives for enhancing flame retardance, wear and chunk resistance, aging resistance (e.g., ozone and UV resistance), and the like. Vulcanization aids, cross-linking agents, oils, accelerators, or other formation aids may also be used.

Specifically, at least one of the elastomer layers 24A-C may incorporate a flame resistance additive. Preferably, all of the elastomer layers 24A-C will incorporate a flame resistance additive. Such an arrangement is advantageous because it ensures the flame resistance of the seal even in the event that one or more layers are damaged (e.g., penetrated or abraded) during repeated door openings/closings use over an extended period of time.

Examples of appropriate flame retardant additives include alumina trihydrate, zinc borate, ammonium polyphosphate, chlorinated paraffin, decabromdiphenyl oxide, antimony oxide, and the like. Such additives may protect the seal by promoting heat shield char formation, and they also may retard the evolution of flammable gases and inhibit flame spread in the vapor phase.

Similarly, the reinforcing layers 26A-C may be formed from any of a variety of materials, either woven or non-woven, and in any desirable weight and orientation. Such materials may include a wide variety of synthetic and manmade fibers, including polyester, nylon, aramid (e.g., Kevlar), glass, polypropylene, cellulose, wool, or others. The fibers may be multi-filament, monofilament, or staple fibers. Additionally, the reinforcing layers 26A-C can be comprised of a single ply of reinforcing material, or they each may comprise multiple individual plies separated by appropriate elastomeric or adhesive layers.

The reinforcing layers 26A-C may be made from the same material and weave type, or they may be made from different materials and/or weaves to produce a seal member 6 having a desired set of physical characteristics. Further, the reinforcing layers 26A-C each may be treated with a compound that enhances bonding of the layers to the material(s) used to form the elastomer layers 24A-D. In one embodiment, the reinforcing layers 26A-C may be coated with an elastomeric latex treatment such as Resorcinol Formaldehyde Latex (RFL). The composition of the elastomeric latex treatment may be selected to enhance adhesion between the reinforcing layers and the elastomer layers, and will depend in part upon the composition of the elastomer used to form the elastomer layers.

At least one of the reinforcing layers 26A-D may also incorporate a flame resistance additive in the form of the elastomeric latex treatment, which may also incorporate a flame retardant compound.

Referring now to FIG. 6, a method is disclosed for making a seal member 6 in accordance with the above described design. Reinforcing layers 26A-C may be cut from a sheet or sheets of woven or non-woven reinforcing material and wound on individual rolls 28A-C. The reinforcing layers 26A-C may then be submerged in a bath 30 of RFL or other elastomeric latex composition 32 and then heated 34 to cure the RFL material on the reinforcing layers. Inner elastomer layers 24B, C may then be applied to the reinforcing layers 24A-C, by pressing or calendaring 36. Inner elastomer layer 24B and reinforcing layer 26B may then be calendared together 38, followed by calendaring 40 the reinforcing layers 26A-C and elastomer layers 24B together, while at the same time applying the outer elastomer layers 24A, D using the same calendaring rolls 40. The resulting composite may then be cut to size at cutting stage 42.

It will be appreciated that where fewer or greater numbers of layers are desired, reinforcement layers 40, 42 are used, additional pressing and/or calendaring steps may be used to apply the requisite additional layers of elastomer 44, 46, 50 and reinforcement.

The preceding series of steps may be used to form a wide sheet of sealing material from which individual seal members 6 may then be cut. Alternatively, the above process could be used to produce seal “strips” which could be cut to length and adhered or otherwise fixed together to form a seal member 6 having a desired shape.

EXAMPLE

An example seal for use in the novel fire resistant mine door sealing system was constructed according to the following configuration:

-   -   (1) Top Elastomer—188 mil thickness of elastomer         (polychloroprene (Neoprene W) compounded with antimony trioxide         and chlorinated paraffin to provide flame retardance);     -   (2) First, second and third reinforcement layers—54 mil         thickness each of polyester-nylon woven fabric, coated with RFL;     -   (3) Between-ply elastomer—24 mil thickness each of elastomer         (same compound as used in the top elastomer);     -   (4) Bottom Elastomer—63 mil thickness of elastomer (same         compound as used in the top and between-ply elastomer).

The overall gauge of the belt was approximately 461 mil. Between-ply elastomer was disposed between each reinforcement layer. The sample was subjected to flame spread testing in accordance with ASTM-E162. Test results are presented below:

Specimen 1 2 3 4 Flame Spread Factor, F_(s) 1.94 1.96 1.55 1.50 Temperature Rise ° C. 9.4 10.6 8.9 10.0 Heat Evolution Factor, Q 1.6 1.79 1.51 169 Flaming Drippings, None None None None minutes:seconds (m:s) Test Duration, m:s 15:0 15:0 15:0 15:0 Radiant Panel Index, Is 3.10 3.51 2.34 2.54

It will be understood that the description and drawings presented herein represent an embodiment of the invention, and are therefore merely representative of the subject matter that is broadly contemplated by the invention. It will be further understood that the scope of the present invention encompasses other embodiments that may become obvious to those skilled in the art, and that the scope of the invention is accordingly limited by nothing other than the appended claims. 

1. A fire resistant mine door system, comprising: a mine door member; a mine stoppage member; and a resilient seal member disposed between said door member and said stoppage member to form an airtight seal between said door member and said stoppage member; wherein said resilient seal comprises a plurality of elastomer layers and a reinforcing layer disposed between an adjacent pair of said plurality of elastomer layers; at least one of said elastomer layers comprising a flame retardant; and wherein said resilient seal member is capable of maintaining said airtight seal at temperatures up to about 500 degrees F.
 2. The fire resistant mine door system of claim 1, wherein the resilient seal comprises first, second and third elastomer layers, and first and second reinforcing layers, the first reinforcing layer sandwiched between the first and second elastomer layers and the second reinforcing layer sandwiched between the second and their elastomer layers.
 3. The fire resistant mine door system of claim 2, wherein the first, second and third elastomer layers comprise polychloroprene, the first and second reinforcing layers comprise a polyester-nylon woven material, and the flame retardant comprises at least one compounds selected from the group consisting of antimony trioxide and chlorinated paraffin.
 4. The fire resistant mine door system of claim 1, wherein at least one of the plurality of elastomer layers comprises polychloroprene.
 5. The fire resistant mine door system of claim 4, wherein the reinforcing layer is a woven material comprising nylon and polyester, said woven material being coated with an elastomeric latex treatment comprising a flame retardant.
 6. The fire resistant mine door system of claim 5, wherein the reinforcing layer is coated with an elastomeric compound.
 7. The fire resistant mine door system of claim 6, wherein the reinforcing layer is impregnated with an elastomeric compound that is different from the compound used to form at least one of the plurality of elastomer layers.
 8. A fire resistant mine closure, comprising: a mine door; a mine stoppage having an opening; and a seal member positioned between the mine door and a perimeter surface of the mine stoppage surrounding said opening, the seal member forming an airtight seal between the door and perimeter surface of the mine stoppage when the door is in a closed position with respect to the stoppage; wherein the seal comprises first and second elastomer layers and a reinforcing layer, the reinforcing layer being disposed between the first and second elastomer layers; the first and second elastomer layers further comprising a flame retardant such that the seal is capable of maintaining said airtight seal at temperatures up to 500 degrees F.
 9. The fire resistant mine door system of claim 8, wherein the seal comprises first, second and third elastomer layers, and first and second reinforcing layers, the first reinforcing layer sandwiched between the first and second elastomer layers and the second reinforcing layer sandwiched between the second and their elastomer layers.
 10. The fire resistant mine door system of claim 9, wherein the first, second and third elastomer layers comprise polychloroprene, the first and second reinforcing layers comprise a polyester-nylon woven material, and the flame retardant comprises a compound selected from the group consisting of antimony trioxide and chlorinated paraffin.
 11. The fire resistant mine door system of claim 8, wherein the plurality of elastomer layers comprise polychloroprene and the flame retardant comprises a compound selected from the list consisting of antimony trioxide and chlorinated paraffin.
 12. The fire resistant mine door system of claim 8, wherein the reinforcing layer is coated with an elastomeric latex treatment comprising a flame retardant.
 13. The fire resistant mine door system of claim 12, wherein the reinforcing layer is impregnated with an elastomeric compound.
 14. The fire resistant mine door system of claim 13, wherein the reinforcing layer is impregnated with an elastomeric compound that is different from the compound used to form at least one of the plurality of elastomer layers.
 15. A fire resistant mine sealing system, comprising: a stoppage positionable within an underground passageway; a door panel pivotably connected to said stoppage; and a fire resistant seal member disposed between said stoppage and said door panel, said seal member comprising a multilayered structure, the multilayer structure comprising a plurality of alternating elastomer and reinforcing layers; wherein said fire resistant seal member forms an airtight seal between said door panel and said stoppage when compressed therebetween, said fire resistant seal member further being capable of maintaining said airtight seal when said door and said stoppage are subjected to temperatures up to 500 degrees F.
 16. The fire resistant mine door system of claim 15, wherein the seal comprises first, second and third elastomer layers, and first and second reinforcing layers, the first reinforcing layer sandwiched between the first and second elastomer layers and the second reinforcing layer sandwiched between the second and their elastomer layers.
 17. The fire resistant mine door system of claim 16, wherein the first, second and third elastomer layers comprise polychloroprene, and the first and second reinforcing layers comprise a polyester-nylon woven material.
 18. The fire resistant mine door system of claim 15, wherein at least one of the plurality of elastomer layers comprises polychloroprene and a fire retardant selected from the list consisting of antimony trioxide and chlorinated paraffin.
 19. The fire resistant mine door system of claim 18, wherein the reinforcing layer is coated with an elastomeric latex treatment comprising a fire retardant.
 20. The fire resistant mine door system of claim 19, wherein the reinforcing layer is impregnated with an elastomeric compound. 